import java.util.Arrays;

public class TestHeap {
    public int[] elem;
    public int usedSize;

    public TestHeap(){
        this.elem=new int[10];
    }

    //初始化数组
    public void initElem(int[] array){
        for (int i = 0; i <array.length ; i++) {
            this.elem[i] = array[i];
            this.usedSize++;
        }
    }

    //重新排序
    public void createHeap(){
        for (int parent = (this.usedSize-1-1)/2; parent >= 0; parent--) {
            siftDown(parent,this.usedSize);
        }
    }

    //向下排序
    //parent 每棵子树调整的时候的起始位置
    //usedSize 判断每棵子树什么时候调整结束
    private void siftDown(int parent, int usedSize){
        int child = 2*parent+1;
        while(child<usedSize){
            //找到左右孩子的最大值
            if(child+1 < usedSize && elem[child] < elem[child+1]){
                child++;
            }
            if (elem[child]>elem[parent]){
                swap(elem,child,parent);
                parent=child;
                child=parent*2+1;
            }else {
                break;
            }
        }
    }

    private void swap(int[] elem,int i,int j){
        int tmp=elem[i];
        elem[i]=elem[j];
        elem[j]=tmp;
    }

    public boolean isFull(){
        return usedSize == elem.length;
    }

    //插入新的元素
    public void offer(int val){
        if (isFull()){
            elem= Arrays.copyOf(elem,2*elem.length);
        }
        elem[usedSize] = val;
        siftUp(usedSize);
        usedSize++;
    }

    //向上排序
    public void siftUp(int child){
        int parent=(child-1)/2;
        while (parent >= 0){
            if (elem[child] > elem[parent]){
                swap(elem,child,parent);
                child=parent;
                parent=(child-1)/2;
            }else {
                break;
            }
        }
    }

    //删除最顶的一位
    public int poll(){
        if (isEmpty()){
            return -1;
        }

        int val = elem[0];
        swap(elem,0,usedSize-1);
        siftDown(0,usedSize-1);
        usedSize--;
        return val;
    }

    public boolean isEmpty(){
        return usedSize == 0;
    }

    //打印最上的元素，不删除
    public int peek(){
        if (isEmpty()) return -1;
        return elem[0];
    }

    //O(N) + O(n*logN) -> O(n*logN)
    public void heapSort(){
        int end =usedSize-1;
        while(end > 0){
            swap(elem,0,end);
            siftDown(0,end);
            end--;
        }
    }

}
